Publications

BACKGROUND

Teleteaching of endoscopy has been limited by the exorbitant cost and time inherent in high-quality digital endoscopy video transmission. The Digital Video Transport System (DVTS) transmitted over advanced networks, such as Internet2 and the Asia-Pacific Advanced Network (APAN), provides a unique infrastructure for sharing uncompressed digital videos of endoscopy. This may allow high-quality, real-time, international training of diagnostic and therapeutic endoscopy techniques at a low cost.

OBJECTIVE

To test the proof of concept of long-distance teaching through live, interactive, high-resolution video transmission by using advanced networks and the DVTS. We used teleteaching of image-enhanced endoscopy techniques as a model.

DESIGN

Prospective multicenter pilot study.

SETTING AND PARTICIPANTS

Trainees, faculty, and staff at 3 international endoscopy units.

INTERVENTION

An image-enhanced endoscopy video lecture with advanced-network technologies.

MAIN OUTCOME MEASUREMENTS

We compared image-based prelecture and postlecture test scores and secondarily assessed technical feasibility and quality.

RESULTS

The DVTS transmitted over advanced networks successfully transmitted uncompressed, high-resolution, digital lectures with endoscopic video (digital video format 720 x 480 pixels). Postsession scores improved. Participants highly rated the technical and informational quality. The majority reported a definite interest in participating in future sessions, with a mean rating (out of 5 [scale 1-5]) of 4.7 +/- 0.5.

LIMITATIONS

Pilot study with a limited number of participants and sessions.

CONCLUSION

The DVTS transmitted over advanced networks such as Internet2 and APAN can provide the infrastructure for transmission of high-resolution, uncompressed video endoscopy for the purpose of teleteaching endoscopy.

BACKGROUND

The fixed dose antimalarial combination of dihydroartemisinin-piperaquine (DP) is a promising new artemisinin-based combination therapy (ACT). We present an individual patient data analysis of efficacy and tolerability in acute uncomplicated falciparum malaria, from seven published randomized clinical trials conducted in Africa and South East Asia using a predefined in-vivo protocol. Comparator drugs were mefloquine-artesunate (MAS3) in Thailand, Myanmar, Laos and Cambodia; artemether-lumefantrine in Uganda; and amodiaquine+sulfadoxine-pyrimethamine and artesunate+amodiaquine in Rwanda.

METHODS AND FINDINGS

In total 3,547 patients were enrolled: 1,814 patients (32% children under five years) received DP and 1,733 received a comparator antimalarial at 12 different sites and were followed for 28-63 days. There was no significant heterogeneity between trials. DP was well tolerated with 1.7% early vomiting. There were less adverse events with DP in children and adults compared to MAS3 except for diarrhea; ORs (95%CI) 2.74 (2.13 to 3.51) and 3.11 (2.31 to 4.18), respectively. DP treatment resulted in a rapid clearance of fever and parasitaemia. The PCR genotype corrected efficacy at Day 28 of DP assessed by survival analysis was 98.7% (95%CI 97.6-99.8). DP was superior to the comparator drugs in protecting against both P.falciparum recurrence and recrudescence (P = 0.001, weighted by site). There was no difference between DP and MAS3 in treating P. vivax co-infections and in suppressing the first relapse (median interval to P. vivax recurrence: 6 weeks). Children under 5 y were at higher risk of recurrence for both infections. The proportion of patients developing gametocytaemia (P = 0.002, weighted by site) and the subsequent gametocyte carriage rates were higher with DP (11/1000 person gametocyte week, PGW) than MAS3 (6/1000 PGW, P = 0.001, weighted by site).

CONCLUSIONS

DP proved a safe, well tolerated, and highly effective treatment of P.falciparum malaria in Asia and Africa, but the effect on gametocyte carriage was inferior to that of MAS3.

BACKGROUND

Conditional knockout mice are a useful tool to study the function of gene products in a tissue-specific or inducible manner. Classical approaches to generate targeting vectors for conditional alleles are often limited by the availability of suitable restriction sites. Furthermore, plasmid-based targeting vectors can only cover a few kB of DNA which precludes the generation of targeting vectors where the two loxP sites are placed far apart. These limitations have been overcome in the recent past by using homologous recombination of bacterial artificial chromosomes (BACs) in Escherichia coli to produce large targeting vector containing two different loxP-flanked selection cassettes so that a single targeting event is sufficient to introduce loxP-sites a great distances into the mouse genome. However, the final targeted allele should be free of selection cassettes and screening for correct removal of selection cassettes can be a laborious task. Therefore, we developed a new strategy to rapidly identify ES cells containing the desired allele.

RESULTS

Using BAC recombineering we generated a single targeting vector which contained two different selection cassettes that were flanked by loxP-loxP sites or by FRT-FRT/loxP sites so that they could be deleted sequentially by Cre- and FLPe-recombinases, respectively. Transfected ES cells were first selected in the presence of both antibiotics in vitro before correctly targeted clones were identified by Southern blot. After transfection of a Cre recombinase expression plasmid ES cell clones were selected on replicate plates to identify those clones which maintained the FRT-FRT/loxP flanked cassette and lost the loxP-loxP flanked cassette. Using this strategy facilitated the identification of ES cell clones containing the desired allele before blastocyst injection.

CONCLUSION

The strategy of ES cell cultures in replicate plates proved to be very efficient in identifying ES cells that had undergone the correct recombination event. This approach facilitates the generation of conditional knock-out mice when large parts of the genome are intended to be flanked by loxP sites.